What the key ratings mean for your BOM
The 387203302: The 15 A per circuit rating at 300 V supports the 14-22 AWG wire range. The dual-wall barrier and single-row layout provide two wire-entry slots for a discrete 2-circuit take-off point. The zinc clear-chromate steel terminal screw finish is the standard trade-off: adequate for indoor panel use, but the clear chromate layer is thinner than a full hot-dip galvanize — in damp or mildly corrosive environments the screws should be checked at maintenance intervals. The PBT/polyester housing does not provide sealing on its own; this is an open barrier block, not a sealed connector.